Question on checpatch.pl warning -- possible unnecessary 'out of memory' message.

[Bas Peters]

Dear all,

I'm fixing up my first driver (drivers/isdn/gigaset) to get some
experience submitting patches. When I run checkpatch.pl on some of the
code, I get the following warning:
	
./drivers/isdn/gigaset/capi.c:337: WARNING: Possible unnecessary 'out of memory' message

The corresponding code is:

        cskb = alloc_skb(CAPI_DATA_B3_CONF_LEN, GFP_ATOMIC);
	        if (!cskb) {
		                dev_err(cs->dev, "%s: out of memory\n",
				__func__);
				                return;
			}

All instances of this warning refer to usage of alloc_skb using the
GFP_ATOMIC flag. Why does checkpatch show this warning? Is it not good
practice to _always_ check whether allocation succeeded or not?

I hope someone can explain the nature of this warning and, if right,
what it should look like.

With kind regards,

Bas Peters